Hydrocarbon oil stabilization



was Sta s P nt;

HYDROCARBON OIL STABILIZATION Harry W. Rudel, Roselle Park, and DilworthT. Rogers,

Summit, N. 3., assignors to Esso Research and Engineering Company, acorporation of Delaware No Drawing. Application November 13, 1950,

Serial No. 195,481

1 Claim. (CI. 44-66) This invention concerns a novel compositionconsisting of a fuel oil containing hydrocarbons derived from crackingoperations and particular compounds as stabilizers for the oil. Thecompounds to be employed as stabilizers consist of the mixture of aphosphatide such as lecithin and an alkali or alkaline earth metal saltof an alkyl phenol sulfide or a phosphorus sulfide reaction productthereof.

This invention broadly concerns hydrocarbon mixtures known as fuel oilsof the nature employed in various burner systems, as diesel fuels, or asdomestic and industrial heating oils. petroleum by a variety of methodsincluding straight distillation from crude petroleum oil, and thermal orcatalytic cracking of petroleum oil fractions.

It has been found that fuel oils consisting completely or in part ofcracked stocks are characterized by an undesirable instability givingrise to the formation of sediment. As a result, such fuel oils may causeclogging of filters, orifices, or conduits associated with the burningsystems in which they are employed.

In accordance with this invention it has been established thatinstability of cracked heating oils may be substantially overcome byincorporating in the heating oil a combination of a phosphatide such aslecithin and an alkali or alkaline earth metal alkyl phenol sulfide orthe phosphorus sulfide reaction product of such a phenol sul-. fide.These two classes of compounds, when employed in combination, are insome way effective in co-acting so that relatively minor proportions ofthe two effectively stabilize a heating oil. Heating oils which may bestabilized by these additives are hydrocarbon mixtures of which morethan about 10% consist of stocks derived from thermal or catalyticcracking operations. More precisely still, the base stocks may becharacterized as petroleum fractions containing a proportion of crackedstocks greater than 10% and falling within A. S. T. M. specificationD-975-48T for diesel fuel oils (grades No. 1-D to 4D inclusive) and A.S. T. M. specification D-396-48T for fuel oils (grades No. 1 to 6inclusive).

An illustration of the types of compounds to be employed in thisinvention are barium isooctyl phenol sulfide and lecithin. Withreference first, to the barium isooctyl phenol sulfide or its equivalentto be included, it may be noted that these are the types of compoundsdisclosed in U. S. Patent Nos. 2,362,291 and 2,451,345. The compounds ofthis nature which may be employed may be explicitly defined as theneutral or basic alkali or alkaline earth metal salts of an alkyl phenolmono or di-sulfide, or the phosphorus sulfide reaction product thereof.The metal ion may thus consist of sodium, potassium, barium, calcium,strontium, lithium, or magnesium. The alkyl group may be a paraffinicgroup of normal, branched, or cycloparafiinic nature containing to 22carbon atoms and preferably containing 8 to 18 carbon atoms. Othersubstituent groups such as halogen and amino groups may be associatedwith the alkyl group. Phosphorus pentasulfide is the preferred sulfideof sulfur Fuel oils may be derived from- 2,808,320 I Patented Oct. 1,1957 to be employed in deriving reaction products of the indicatedsulfides. As these compounds are now well known to the art, no furtherdescription of them is considered necessary. It may be noted thatcompounds of the class described are commercially available. In generalthey are, prepared as a concentrate of the active ingredient in a heavyoil vehicle. Howevenin the data which follows, it is to be understoodthe quantities indicated represent the amount fof active ingredientexclusive of the vehicle in which it is contained.

With regard to the lecithin to be employed, it may be noted thatlecithin is a monoamino-monophosphatide containing similar or dissimilarradicals corresponding to the radicals of stearic acid, palmitic acid orsimilar fatty acids. Lecithinfwhich is commercially available, is amixture of compounds of the above-identified character.

As indicated, it has been found that when employing mixtures of lecithinand the metal salts of the indicated alkyl phenol sulfides, synergisticresults are provided to effectively stabilize a fuel oil. As will beshown, it is particularly notable that small proportions of either ofthese classes of compounds alone are not capable of cffectivelystabilizing a fuel oil. However, in some manner, when employed togetherin combination, small proportions of lecithin and one of the metal saltsare peculiarly effective in stabilizing fuel oil. Due to this 00-.operative synergistic effect of these additives it is presentlycontemplated that about equal proportions of the additives should beemployed. Not more th-anabout 0.05 weight percent of the combinedadditives are required,,and generally, about 0.02 weight percent is ef-Qfective in stabilizing heating oils.

stood that other known additives may, if desired, beincorporated in.theheating oil in the conventional manner. Thus ifdesired, constituentssuch as alcohols, glycerin and glycol esters and ethers, alkylphosphoric acid and thiopho sphoric acid derivatives, and otherconventional additives may be employed in addition. It is particularlycontemplated that rust inhibitors be included in the fuel oils of thisinvention. Examples of such rust-inhibitors are the metal salts ofnaphthenic acids, sorbitanesters,

- I and esters of pentaerythritol.

The nature of this invention will be fully understood from the followingexamples of the invention.

A commercial heating oil was tested for stability as the oil wasreceived and after addition of various types of additives to the oil.The oil was a blend consisting of 20 to 30% cat-alytically crackedstock, 50 to 40% thermally cracked stock, and 30% virgin stock. Typicalinspections of this type of oil are as follows: Gravity, A. P. I. 34.1Color (Tag Robinson) 11% Flash F. 158 Sulfur (percent) 0.56 Anilinepoint F. 130 Neutralization No. 0.07 Dist.:

I. B. P. (F.) 342 10% 420 50% 484 576 F. B. P. 628 Carbon residue on 10%bottoms (percent) 0.82

In a series of additive tests which were conducted, a particular metalsalt of an alkyl phenol sulfide, was added to. this heating oil,lecithin alone was added to the heating oil, and finally, differentweight combinations of lecithin and the metal salt were added to theheating oil. The resulting heating oil compositions were then tested forstability in a test in which the heating oil was stored in a glassbottle for a period of 16 hours while being It is tobe under--maintained at a temperature of 210 F. At the end of this time theheating oil was filtered and the amount of sludge accumulating duringthe storage period was then quantitatively determined. The results ofthese tests are indicated in the table below;

Heating oil stability tests 0.008 Wt. Percent Barium isooctyl PhenolSulfide and 0.005 Wt. Percent Lecithin 2 0.004 Wt. Percent BariumIsooctyl Phenol Sulfide and 0.01 Wt. Percent Lecithin 2 0.008 Wt.Percent Sulfur reaction product of Barium Isooctyl Phenate and 0.005 Wt.Percent Lecithin 1 0.008 Wt. Percent Phosphorus Pentasulfide reactionproduct of Barium Isooctyl Phenol Sulfide and 0.005 Wt. Percent Lecithin0.005 Wt. Percent Potassium Isooctyl Phenol Sulfide and 0.005 Wt.Percent Lecithin 1 Referring to the table, it will be noted that theuntreated heating oil provided 28 mg. of insoluble matter per 600 g. ofthe heating oil during the stability test. This amount of sedimentformation is so great as toclearly indicate that the oil was ofunsatisfactory stability. The upper portion of the table shows theresults of adding small proportions of lecithin and various metal phenolsulfides or their phosphorus sulfide reaction products individually todifferent heating oil blends. It will be noted that in each case whenonly a single additive isemployed, little if any improvement instability is obtained. Thus, as the table shows, when the heating oilcontained about 0.1 wt. percent of either lecithin or barium isooctylphenol sulfide, or potassium isooctyl phenol sulfide, or the sulfurreaction product of barium isooctyl phenate, or the phosphoruspentasulfide reaction product ofbarium isooctyl phenol sulfide, for themost part, no improvement in stability was obtained.

Finally, in the lower portion of the table, data is given showingdifierent combinations of lecithin and each of the metal phenol sulfidesor their derivatives when employed in combination with the lecithin. Ineach case the total weight percent of the combined additives employedwas again about 0.01%, or somewhat more. However, it will be noted thateach of the combinations were effective in substantially eliminatingsediment formation during the stability tests.

The data presented in the table is representative of the broad class ofcompounds embraced within this invention. Thus, the data bears out thesynergistic efiects of lecithin and either an alkali or alkaline earthmetal salt of an alkyl phenol sulfide. The data also shows that aphosphorus sulfide reaction product of metal salts of an alkyl phenolsulfide also provides a synergistic eifect with lecithin when used in aheating oil.

It should also be noted that when employing the combination .ofadditives, the color of the heating oil was also stabilized. Thus, inthe cases when either lecithin alone or any one of the other indicatedadditives was employed, it was found that the oil'darkened appreciablyduring the stability test. However, when any of the combinations ofadditives was employed, this change in color did not occur.

What is claimed is:

A fuel oil composition consisting of a major proportion of hydrocarbonsboiling in the heating oil boiling range including more than about 10%cracked stocks and a 7 minor proportion of a synergistic combination oflecithin and barium iso-octyl phenol sulfide, said combination beingpresent in a sediment stabilizing amount but constituting not more thanabout 0.02 weight percent of said composition, said combinationconsisting of about 4 to 16 parts by weight of said compound per 10parts of lecithin.-

References Cited in the file of this patent UNITED STATES PATENTS2,165,651 Rees et a1 July 11, 1939 2,207,430 Burk et a1. July 9, 19402,252,985 Rutherford et al. Aug. 19, 1941 2,378,793 Rudel June 19, 19452,385,158 Paulsen Sept. 18, 1945 2,437,041 Proell Mar. 2, 1948 2,451,345McMab Oct. 12, 1948 2,524,864 Wies et al Oct. 10, 1950

